For a while, I have been using ido to quickly jump between buffers and files by just typing any part of the file/buffer name I want. In fact, typing any sequence of letters narrows the interactive search to candidates with names that contain those letters in that order:

fb -> Foobar, FrancisGailBrown

But for finding method definitions in a big source file, I have always just used isearch. It turns out that there is a better way.